Conventional C-clamps have been held against rotation and in a desired position relative to a workpiece being clamped by any of several expedients, when turning their clamping screws. These expedients have included grasping the C-frames by hand, allowing the C-frames to rotate until making contact with the workpieces, or providing blocks or wedges between the C-frames and stationary objects as may be available at the immediate work-site. The rotative torques to be resisted by these expedients are dependent upon the clamping forces desired against the workpieces and the amount of friction developed between the fixed clamping surfaces and the workpieces. The resultant C-frame rotative torques are, in some instances, of considerable magnitudes, especially when large size or heavy duty C-clamps are used, as such C-clamps employ clamping screws actuated by sliding cross-bars or by wrenches to facilitate the application of high tightening or loosening torques. To resist such rotative torques by grasping the C-frames by hand, or by other expedients, can be unsafe, inconvenient and possibly damaging to the workpieces.
Although C-clamps have been used for decades, the difficulty of holding them while tightening or loosening their clamping screws, and the attendant risks of injuries to hands and workpieces, has been accepted as inherent by those skilled in the art. Prior art C-clamps have not provided effective means for eliminating either this difficulty or the risks attendant thereto. The present invention described hereinafter provides a simple, user option for eliminating both the difficulty and the risks.